OPINION OF THE COURT BY
LUM, C.J.This is an appeal from a jury conviction of one count of medical assistance fraud in violation of Hawaii Revised Statutes (HRS) § 346-43.5 (Supp. 1984).1 Appellant’s primary contention on appeal is that a fatal variance exists between the offense charged and the evidence adduced at trial. We agree and reverse.
*344I.
On May 25, 1984, Appellant Dr. Richard Sword, a Maui psychologist, was indicted on thirty-two counts of Medicaid fraud. The indictment alleged that Appellant had knowingly and wilfully lied on Medicaid claim forms in order to receive unauthorized compensation. The jury acquitted Appellant of thirty-one of the counts and convicted him only of Count 19.
Counts 19 through 32 involved claims for therapy sessions with patient Anatta B. Count 19 specifically pertained to a claim form filed on July 21, 1983.2 Appellant’s allegedly false statement was that Dr. Jack Lewin was Anatta B.’s “referring physician” when no such referral had been made. Medicaid regulations provide that a psychologist’s services are not compensable unless the patient has been referred by a practicing physician.
From the beginning of its investigation, the State’s only theory was that Dr. Lewin had never heard of or referred Anatta B., and that while Appellant was aware of this, he nevertheless used Dr. Lewin’s name in order to fraudulently obtain Medicaid payments.3 On the July 21, 1983 claim form, Appellant had billed Medicaid for two therapy sessions with Anatta B. — one on June 2, 1983 and the other on July 19, 1983. Medicaid paid him $19 for each session.
Contrary to the State’s claim, the evidence showed that Dr. Lewin had in fact referred Anatta B. to the Appellant in early June 1983. *345Anatta B., called as a surprise defense witness, testified that she obtained the disputed referral herself after Appellant had refused to treat her without it.4
After Anatta B.’s testimony on direct examination, the State changed theories. Its new contention was that Appellant provided therapy services on June 2, 1983 and then obtained the referral afterward.5 In its closing arguments to the jury, the State contended that a retroactive referral was the same as having no referral at all.
The jury apparently found that Dr. Lewin’s referral did not cover the June 2, 1983 therapy session, but did cover all subsequent therapy sessions.6 On this basis, Appellant was convicted of Count 19 and acquitted of Counts 20 through 32.
II.
The purpose of an indictment is “to apprise the accused of the charges against him, so that he may adequately prepare his defense, and to describe the crime charged with sufficient specificity to enable him to protect against future jeopardy for the same offense.” Carvalho v. Olim, 55 Haw. 336, 344, 519 P. 2d 892, 898 (1974). See State v. Daly, 4 Haw. App. 52, 54-55, 659 P.2d 83, 85 (1983).
A variance is a disagreement between the allegations in the indictment and the proof of some matter that is legally relevant to the charge. Territory v. Coe, 37 Haw. 601, 606 (1947). To be fatal, a variance must *346be both material to an essential element of the offense and prejudicial to a substantial right of the accused. See State v. Nases, 65 Haw. 217, 218, 649 P.2d 1138, 1139 (1982); State v. Peters, 44 Haw. 14, 352 P.2d 329, 331 (1959).
Philip H. Lowenthal {Anthony L. Ranken with him on the briefs) for Defendant-Appellant. Winfred K. T. Pong {George H. Yamamoto with him on the brief) Deputy Attorneys General for Plaintiff-Appellee.The State contends that the indictment stated each material element of the offense charged and was thus sufficient to apprise Appellant of what he had to meet in order to prepare his defense.
We agree with the State but the question is not the sufficiency of the indictment. Rather, the question is whether there is a fatal variance between the evidence proved and the material elements of the offense charged in the indictment. We hold that such a fatal variance occurred. Appellant was indicted on Counts 19 through 32 for allegedly using Dr. Lewin as a “referring physician” when no such referral had ever been made at all. At trial, the evidence showed that Dr. Lewin had made the referral shortly after June 2, 1983, before any of the disputed claim forms were filed. Any possibility of the actual referral date serving as the basis of criminal liability arose only as prosecutorial afterthought.7
The State’s claim that a variance, if any, resulted in no prejudice to Appellant is equally without merit.
Reversed.
HRS § 346-43.5 (Supp. 1984) provides in pertinent part:
It is unlawful for any person to knowingly and wilfully make or cause to be made to the medical assistance program any false statement or representation of a material fact in any application for any benefit or payment for furnishing services or supplies, or for the purpose of obtaining greater compensation than that to which the person is legally entitled or for the purpose of obtaining authorization for furnishing services or supplies.
Count 19 of the indictment states:
On or about July 21, 1983, in the County of Maui, State of Hawaii, RICHARD M. SWORD, Ph.D., did knowingly and wilfully make or cause to be made to the Hawaii Medical Assistance (Medicaid) Program in an application for payment for furnishing services to patient Anatta B. false statements of a material fact, to wit, that patient Anatta B. was referred to him by Dr. Jack Lewin when in fact Dr. Jack Lewin had not made the referral, thereby committing the offense of Medical Assistance Fraud in violation of Section 346-43.5 of the Hawaii Revised Statutes.
Except for the dates involved, the allegations in Counts 20 through 32 were identical to those in Count 19. They named Dr. Lewin as Anatta B.’s referring physician, but involved claim forms filed after July 21, 1983.
The State sought and obtained a grand jury indictment on this theory and then used it successfully to defeat a pretrial motion to dismiss the indictment. In his opening remarks to the jury, the State’s attorney once again pressed the contention that Dr. Lewin had neither heard of nc referred Anatta B. to the Appellant.
Anatta B. was produced as a surprise defense witness after the State attorney told the jury that she was unavailable. Over the State’s objection, she testified in part as follows:
I went to see Dr. Sword, and before he could see me he said he needed a referral And I’m not sure if he mentioned Jack Lewin or I mentioned Jack Lewin, but I called Jack Lewin and asked him to refer me to Dr Sword. And he said that he didn't normally do that. And then he said that I needed to choose my own doctor because I needed help at the time. And I thought that Dr Sword could help me, that I had a rapport with him, and that I could talk to him. And then he said “All right.”
And then 1 went to Dr. Sword and told him that Dr. Jack Lewin said “All right,” and then I started seeing Dr. Sword.
The precise date of the referral was unclear, but the testimony indicated that it came one to three days after the June 2,1983 visit. The jury was not charged as to when a referral is required under the Medicaid regulations.
The State in its answering brief concedes that Dr. Lewin did, in fact, refer Annata B. some time after June 2, 1983.
The legal question of whether a referral may actually be applied retroactively for purposes of Medicaid reimbursement was not litigated in the trial below. The related question of whether a claim for services provided before the referral gives rise to the same criminal liability as having no referral at all was likewise not litigated below. We therefore make no rulings on these matters here.